The present invention generally concerns surgical instruments and, more particularly, surgical cutting and fastening instruments.
Endoscopic surgical instruments are often preferred over traditional open surgical devices since a smaller incision tends to reduce the post-operative recovery time and complications. Generally, these endoscopic surgical instruments include an “end effector”, a handle assembly and an elongated shaft that extends between the end effector and the handle assembly. The end effector is the portion of the instrument configured to engage the tissue in various ways to achieve a desired diagnostic or therapeutic effect (e.g., endocutter, grasper, cutter, staplers, clip applier, access device, drug/gene therapy delivery device, and energy device using ultrasound, RF, laser, etc.).
The end effector and the shaft portion are sized to be inserted through a trocar placed into the patient. The elongated shaft portion enables the end effector to be inserted to a desired depth and also facilitates some rotation of the end effector to position it within the patient. With judicious placement of the trocar and use of graspers, for instance, through another trocar, often this amount of positioning is sufficient. Surgical stapling and severing instruments, such as those described in U.S. Pat. No. 5,465,895, are examples of an endoscopic surgical instrument that successfully positions an end effector by insertion and rotation.
Over the years, various approaches have been taken by medical component manufacturers to reduce the overall cost of such endoscopic surgical instruments. While some of these approaches have been successful at addressing at least some of the user's needs, they still fall short of addressing other needs. For example, prior end effector designs employ an anvil that is pivotally coupled to a cartridge-supporting channel such that, when tissue is clamped between the anvil and the cartridge, the anvil tends to undesirably “roll” the tissue out of the desired position, making it difficult for the surgeon to precisely clamp the tissue in the desired position. Those approaches and others also employ mostly machined components which are more costly to manufacture and thus inflate the overall costs of the instrument.
Consequently there is a need for an end effector arrangement for a surgical cutting and fastening instrument that addresses the above-mentioned concerns by providing end effectors that are equipped with anvils that can close onto the channel in a substantially parallel fashion and which do not necessarily require the use of all machined components.